*To*: mathgroup@smc.vnet.net*Subject*: [mg12004] Re: Please help: How to assert that an object is a matrix ???*From*: Adrian Cable <megalith@jimc.demon.co.uk>*Date*: Fri, 17 Apr 1998 03:40:40 -0400*Organization*: MeGALiTH Software Ltd*References*: <6gr6j7$8mf@smc.vnet.net>

> where GL, GT, IL, etc., are not elements but (sub-)matrices themself. I > want to perform algebraic transformations on A, but I want element > multiplication to be non-commutative and inversion to use Inverse > rather than 1/element. > > Can I somehow trick Mathematica to assume that elements are matrices? I may have misunderstood the question, but, for example, if you wish GL to be a general 2x2 matrix, have you tried something like: GL = {{a,b},{c,d}} Thanks, cheers, Adrian Cable.